Spectroscopy of the Potential Profile in a Ballistic Quantum Constriction

TL;DR

This paper develops a theoretical model to analyze the nonlinear current-voltage behavior in ballistic quantum constrictions caused by impurity-induced potential profiles, enabling impurity characterization.

Contribution

It introduces a theory linking nonlinear I-V features to impurity potentials and positions in ballistic quantum constrictions.

Findings

Nonlinear I-V features arise from above-barrier reflection due to impurities.

The model allows determination of impurity distances and potential magnitudes.

Nonlinearity occurs at small voltage scales, facilitating impurity analysis.

Abstract

We present a theory for the nonlinear current-voltage characteristics of a ballistic quantum constriction. Nonlinear features first develop because of above-barrier reflection from the potential profile, created by impurities in the vicinity of the constriction. The nonlinearity appears on a small voltage scale and makes it possible to determine distances between impurities as well as the magnitude of the impurity potentials.